1. Field of the Invention
The present invention relates to an optical connector including an optical module. In particular, the present invention relates to an optical connector having a high light transmission efficiency between a sleeve and an optical element such as a photodiode or an LED.
2. Description of the Related Art
Japanese Unexamined Patent Application Publication No. 2000-304980 (FIGS. 4 and 5) describes an optical connector including a receiving sleeve and a transmitting sleeve that are disposed in a housing.
In the optical connector described in Japanese Unexamined Patent Application Publication No. 2000-304980, a light receiving module and a light transmitting module are respectively mounted in the first cylindrical socket and the second cylindrical socket so that small diameter surfaces of the sleeves face the light receiving module and the light transmitting module.
Japanese Unexamined Patent Application Publication No. 2002-23025 (see FIGS. 7 and 8, and paragraph 0073) describes an optical connector in which a cylindrical socket is formed in a housing. When a guide portion of a sleeve is inserted into the cylindrical socket, an end of the guide portion contacts a stepped portion formed on the cylindrical socket. Thus, the gap between a receiving device or a transmitting device and a ferrule assembly is minimized and a gap loss in the optical axis direction is minimized.
However, with the optical connectors described in Japanese Unexamined Patent Application Publication Nos. 2000-304980 and 2002-23025, one of the ends of the sleeve that faces the light receiving module or the light transmitting module (hereinafter referred to as the “facing end”) is a free end.
Therefore, these optical connectors have a problem in that the facing end is easily displaced in a direction perpendicular to the optical axis and therefore it is difficult to reduce the gap loss between the light receiving module or the light transmitting module and the facing end of the sleeve.
Moreover, in existing optical connectors, the end face of a sleeve that faces the light receiving module or the light transmitting module is a flat surface. Therefore, in particular in the case of the light emitting module, when light emitted by the light emitting module enters the sleeve through the flat end face, a part of the light may be reflected, which causes a problem in that the light transmission efficiency between the light emitting module and the sleeve is low, i.e., the optical coupling loss is large.